I've had a reply, Geoff - here you go:
"You are right about the repotting and the roots, that goes for both. Both need rain water. As for the soil, that's usually a mix of peat, perlite and sand. Best buy a designated compost for them, they all like that.
And no carnivore likes drying out completely.
Oh, and they all need a good amount of light.
Saracenia are the more uncomplicated ones. You can sit them in a saucer and keep that topped up with water. They will also grow happily in such a tank. What I did with both was to put some clay granules down first and then add the soil.
The saracenia can go right on top of that, but nepenthes are more finicky. They don't like stagnant water around their roots. So If you want to keep them with other carnivores in such a tank, make the clay granule layer a bit thicker for them so they sit higher than the other plants. If their rootball can drain freely they will feel better. Once they have pitchers one can add a bit of water to the pitchers and they will use that to supplement their water needs without having rotting roots. You could even hang them from the sides of the tank without their pot touching the ground. Keep them moist, but allow excess water to drain.
All carnivores love being sprayed with rain water."
Hope that helps